ReferenceVersionRules

Whether a reference needs to be version specific or version independent, or whether either can be used

This code system http://hl7.org/fhir/reference-version-rules defines the following codes:

Code	Display	Definition
either	Either Specific or independent	The reference may be either version independent or version specific
independent	Version independent	The reference must be version independent
specific	Version Specific	The reference must be version specific